1. Field of the Invention
The present invention relates to a rechargeable battery temperature detection method, a power management device and an electronic system, and more particularly, to a rechargeable battery temperature detection method, a power management device and an electronic system that can switch circuits according to states of a processor in order to prevent temperature of a rechargeable battery from being out of control.
2. Description of the Prior Art
Along with the ever-increasing popularity of portable electronic devices, demand for a rechargeable battery has grown dramatically in recent years. When recharging a rechargeable battery, however, the electric current passing through will release heat (known as joule heating), which causes the rechargeable battery to become hot. If the rechargeable battery becomes too hot, it may experience thermal runaway, become damaged, or even explode. To ensure charging safety, a thermistor may be disposed in the portable electronic device in proximity to the rechargeable battery and adapted for a fuel gauge to detect temperature of the rechargeable battery. The fuel gauge determines the temperature of the rechargeable battery according to the resistance of the thermistor, and sends a temperature sensing result to the processor. The processor then transmits the temperature sensing result to the charging control circuit, which can control a magnitude of a charging current flowing from a charging circuit to the rechargeable battery to prevent thermal runaway.
The temperature sensing results detected by the fuel gauge must be ceaselessly transmitted to the charging control circuit through the processor. If the processor crashes, the charging control circuit cannot adjust the charging current according to the temperature sensing result, and charging safety will be put at risk. Moreover, in order to ensure that the charging control circuit can accurately determine the temperature of the rechargeable battery even when the portable electronic device is in a sleeping or a shutdown state, the processor must consume certain amounts of electricity to transmit the temperature sensing result to the charging control circuit. Accordingly, ensuring charging safety and saving power even when the processor is executed in different states is a main objective in the field.